Originally Posted by
milypan
Do we know that for sure? B752 has 57t to work with (MTOW – OEW), of which ~19t goes to pax/luggage in a TATL configuration, leaving 38t. But the tanks only hold ~34t, so that appears to be the limiting factor. A321XLR MTOW is forecast at 101t. At 101t it would have 50t to work with, of which ~18t goes to pax/luggage, so ~32t of fuel. I'm unclear on the tank size of the XLR. The A321neo holds ~24t, and the new rear center tank can hold almost 10t; if they're additive then it could hold a full 32t.
At any fuel load of 29t or more, the XLR will surely give the 752 a run for its money in range. At near-equivalent fuel loads I can't see how it could possibly have less range. Yes, it will take longer to get to FL360 or above, but that's going to be more than compensated for by the GTF/LEAP engines that have considerably lower SFC and lower max thrust than the PW2040.
Airbus has published (and promised) a range of 4700 nm for the A321xlr. The 752 has a published range of 3,900. Lots of reports that Airbus is hitting it's targets, but I guess we will not know until first deliveries in 2023. I don't know the loading conditions where it has a range of 4700 nm (probably could dig deeper and find them) but given the much lighter frame and engines that are about 30% more efficient per seat, as the math you did shows, there is no reason to think that the range will not exceed that of the 752 in a similar configuration by a reasonable amount.
I think the a321xlr will allow an airline to do routes (like EWR-Berlin) and even longer new routes e.g. from ORD or a route like IAD-Berlin, which were outside of the range of the 757 resulting in tech stops.